Ancient viral DNA was found to regulate the expression of the human gene

A new international study suggests that the ancient viral DNA integrated into our genome, which was long -fired as genetic “garbage”, can actually play strong roles in the regulation of gene expression. Focusing on a family of sequences called MER11, researchers from Japan, China, Canada and the US have shown that these data has evolved to influence the way genes activate and disable, especially in early human development.

Transferred elements (TES) are repeated DNA sequences in the genome derived from ancient viruses. For over millions of years, they have spread throughout the genome through copying and invoicing mechanisms. Today, TES are almost half of the human genome. While they were once considered not to serve useful function, recent research found that some of them act like “genetic switches”, controlling the activity of nearby genes in specific cell types.

However, because TEs are particularly repetitive and often almost identical in sequence, they can be difficult to study. Specifically, the younger TE families such as Mer11 have been wrongly categorized into existing genomic databases, limiting our ability to understand their role.

To overcome this, the researchers developed a new method of classifying TES. Instead of using typical comment tools, they grouped Mer11 sequences based on their evolutionary relationships and how well they were maintained in primates’ genomes. This new approach has allowed them to divide Mer11a/B/C into four separate subfoies, namely Mer11_G1 to G4, ranging from the older to the younger.

This new classification has previously revealed hidden patterns of regulatory genes. The researchers compared the new Mer11 subfoies in various epigenetic indicators, which are chemical labels in DNA and the related proteins that affect gene activity. This has shown that this new classification was aligned closely with the actual regulatory function compared to previous methods.

To immediately check whether Mer11 sequences can control the gene expression, the group used a technique called Lentimpra (a massive parallel reference test). This method allows for the testing of thousands of DNA sequences at the same time as they insert them into cells and measure how much each enhances gene activity. The researchers applied this method to about 7000 Mer11 sequences from humans and other primates and measured their effects on human stem cells and early stages.

The results showed that Mer11_G4 (the latest subfamily) showed a powerful ability to activate gene expression. It also had a separate set of regulatory “patterns”, which are small DNA segments that serve as connection positions for transcription factors, proteins that control when genes are activated. These patterns can dramatically affect the way genes respond to development signals or environmental signs.

Further analysis revealed that Mer11_G4 sequences in humans, chimpanzees and macaques had accumulated slightly different changes over time. In humans and chimpanzees, some sequences have gained mutations that could increase their regulatory potential during human stem cells.The young Mer11_G4 is linked to a separate set of transcription factors, indicating that this team has won different regulatory functions through sequence changes and contributes to accumulation,The leading researcher Dr. Xun chen explains.

The study offers a model for understanding how “rubbish” can evolve into regulatory elements with important biological roles. By detecting the evolution of these sequences and directly testing their function, the researchers have shown how ancient viral DNA has been co-opted in shaping gene activity into primary.

‘Our genome has been identified in sequence for a long time, but the operation of many of its parts remains unknown“, Coordinating Auther Dr. Inoue Notes. Transferred evidence is believed to play important roles in genome evolution and their importance is expected to become clearer as the research continues to go ahead.